Dentist&#39;s drill



A. PRUFER DENTIST'S DRILL Oct. 12, 1965 2, Sheets-Sheet 1 Filed Sept. 4, 1962 Oct. 12, 1965 A. PRUFER 3,21

DENTISTS DRILL Filed Sept. 4, 1962 2 Sheets-Sheet 2 Fig.5

Unvenfar:

United States Patent 3,210,847 DENTISTS DRILL Albert Priifer, Seulingen, Duderstadt, Germany Filed Sept. 4, 1962, Ser. No. 221,246 1 Claim. (CI. 3227) The present invention relates to a drill particularly designed for dentists.

These drills are known in the form of stationary machines having an electric drive and a gearing. The shank of the drill is journalled in a handle or in an angle piece which is connected to the motor by means of a sliding hinge connection, a linkage, and a string drive or a flexible shaft. Portable drills are also known, in which the motor with its mains connection can be carried and in which the angle piece is driven by means of the flexible shaft. Furthermore, portable post drilling machines for connection to the mains and combined stationary drilling machines for electric and foot operation are known. All known machines are rather bulky, because of the transmission members, like string drives, linkages, sliding connections, flexible shafts, etc. used between the driving motor and the handle or angle piece, and which affect the use of the handle or angle piece which is the actual working tool. Furthermore, the machines are diflicult to transport, and because of their complicated construction they are very expensive.

It is one object of the present invention to provide a drill designed for dentists, which eliminates these deficiencies by having the drive mechanism formed of a weak-current motor fitted directly to the handle or angle piece provided with the drill chuck. Completely safe for the patient, the motor can be operated as a lowvoltage, direct-current motor and at speeds of approximately 12,000 revolutions or more per minute. Such motor is of very small weight (less than 90 grs.), and it can be accommodated in a housing which is easily attached to the handle or angle piece. Mounted on the motor shaft is a plug-in or coupling cooperating with a corresponding part of the coupling on the shaft driving the drill chuck. Preferably, the coupling is made of plastic material.

It is another object of the present invention to provide a drill designed for dentists, which uses as a source of power supply a battery, an accumulator, or the line current. For easy exchange, a battery or an accumulator may be arranged directly on the handle or angle piece, or a separate circuit line is used to enable the dentist to carry the power source in a pocket or like a wrist watch and to connect it to the driving motor by means of a cable.

When using the mains supply, it is of advantage to use a connection box having a transformer, a rectifier, and if necessary, a variable resistor for adjusting the speed of the motor according to requirements.

The operation of the device is very simple, because the machine does not require any large installation. The motor which is attached directly to the handle or angle piece hardly increases the Weight of the latter. It is easily switched on and off by a switch provided directly on the motor or by a switch which is actuated by a finger or by the hand carrying the handle or angle piece.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

FIGURE 1 is a perspective view of an angle piece provided with a driving motor;

FIG. 2 is a perspective exploded view of the rear part of the angle piece with the motor;

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FIG. 3 is a perspective view of an embodiment including a battery;

FIG. 4 is a perspective view of the machine in operation; and

FIG. 5 is a circuit diagram of a mains connection box.

Referring now to the drawings, and in particular to 'FIG. 4, the drill comprises an angle piece 1, a head piece 2 carrying the drill chuck for the dental tool 3. The front end of the angle piece 1 accommodates in its head piece 2 the drill chuck for the tool 3, as for instance a bur, a miller, a grinding or polishing wheel, or the like. A drive shaft (not shown) is journalled inside of the angle piece -1 and of the head piece 2.

The rear part of the angle piece 1 forms a coupling member 4 to enable the angle piece 1 to be attached to a driving source, as an electric motor 5 disposed in a coupling member 6. For this purpose, a dog clutch 7, preferably of plastic material, is provided on the drive shaft (not shown) in the angle piece 1, the dog clutch 7 engaging a complementary clutch on the motor shaft when fitting together the coupling members 4 and 6. A resilient pawl 8 is mounted on the coupling member 6 and has an enlargement 8 at its free end, which enlargement 8 is received in a corresponding recess '8 in order to retain the two coupling members 4 and 6 in their coupled positioni Preferably, the grip of the angle piece 1 is made of special synthetic material and houses the circuit lines of a switch 15 and -16. The same material may also be used for the housing and/or the connecting sleeve of the electric motor 5. Plug and socket connections (not shown) are provided for the circuit lines in the angle piece 1 and in the housing of the motor -5 and its connecting sleeve 6, so that upon attaching the angle piece 1, the circuit lines are connected at the same time. The special synthetic material ensures complete insulation from the current-carrying parts.

Referring now again to the drawings, and in particular to FIG. 3, disclosing another embodiment of the present invention, the housing of the electric motor 5 is provided with plugs 9 to fit into a socket 11 of a battery '10. It is possible to use a battery housing in which several conventional plate-type batteries or accumulators are arranged.

According to the embodiment disclosed in FIGS. 1 and 2, the electric motor 5 is connected by means of a detachable cable 12, with a battery 16 which can be carried, for instance, like a wrist watch by an operating dentist. It is possible, of course, to arrange the battery 13 also at any other convenient location.

A direct-current motor 5 is used for driving the machine, which motor operates at a speed of 12,000 revolutions per minute and a working voltage of up to 30 v. In order to switch on and oil the motor 5, a spring-biased switch, as shown in 'FIG. 1, or a sliding switch 15 and 16 may be used which is directly fixed on the handle or angle piece 1 and which is easily actuated during work by the hand holding the angle piece 1.

When the motor 5 is driven from the mains, a svn'tch box 25 is provided which, on the one hand, is connected to the mains by means of a cable 17, and on the other hand to the electric motor 5 by means of a cable 24. Inside of the switch box 25, a switch 18, a fuse 19, a transformer 20, a rectifier 21 and a variable resistor 22 for adjusting the speed of the motor 5 are arranged. This additional device is easy to carry, as Well as the angle piece -1 provided with the bur 3 so that the dentist is independent from any of the installations used before. Various different embodiments are possible without departing from the spirit of the present invention.

While I have disclosed several embodiments of the present invention, it is to be understood that these embodiments are given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claim.

I'claim:

A dental drilling machine, comprising an angle piece having one free end,

a head piece secured to said free end of said angle piece and including a chuck,

p a tool releasably received by said chuck of said head piece,

a low current, high-speed electric motor having a housing and releasably and slidably secured to said angle piece,

said angle piece extending axially from said motor housing,

a movable electric current source spaced apart from said electric motor and adapted to be carried by the operator of said machine,

a cable feeding electric current from said current source to said motor,

a spring-biased switch disposed in the circuit of said electric motor and secured to said angle piece and remote and forward from said electric motor, said References Cited by the Examiner UNITED STATES PATENTS 950,759 3/ 10 Weiner 32-26 X 2,370,632 3/45 Blair 32- 27 2,81 .9,285 4/58 Steiner 31050 2,861,462 11/ 58 Hussar 3=2-*27 X 2,866,267 12/5 8 Fletcher et a1.

3,094,780 6/63 Maurer et al. 32- 28 3,109,238 ll/ 63 Marks 32-27 20 DELBERT B. LOWE, Primary Examiner.

ROBERT E. MORGAN, RICHARD A. GAUDET,

Examiners. 

